In a system for which reliability is required, the system is duplicated. That is, two processing units are prepared, and a first processing unit is used as a current system and a second processing unit is on standby for a trouble occurring in the first processing unit. The second processing unit is provided with programs and data needed for processes to promptly inherit works when a trouble occurs in the first processing unit. Such a mode is called a hot standby mode.
In addition, as to a transaction process, although one of the transactions can be carried out in a short time, a large number of transactions which simultaneously occur can not be processed by a single processing unit in realtime. Thus, there is a load sharing mode in which, for distribution of load, the transactions which have occurred are distributed among a plurality of processing units and processed. In this load sharing mode, in a case where a trouble occurs in a processing unit, transactions are not distributed to the processing unit having the trouble.
To form a system in the hot standby mode or the load sharing mode, a large number of programs are needed.
In addition, in recent years, due to decreasing of the price of the processing unit and the necessity of processing many works, operations in a range between an operation in which two or three large general-purpose computers are used and an operation in which many processing units are used are desired. For example, the number of cases where a plurality of processing units each of which is mounted in a frame and named a cluster are connected to each other is increasing (a plurality of CPUs may be included in a single cluster). With the spread of such a case where a plurality of clusters are connected to each other, it is desired that works are efficiently inherited when a trouble occurs in one of the clusters.